Sarcopenic obesity is common among kidney transplant recipients. Fluid volume status has not been well-investigated following kidney transplantation. This thesis aimed to explore the effects of body composition, including fat mass, muscle mass and fluid volume status, on post-transplantation morbidity and fatigue. These are potential contributing factors to long-term patient- and graft- survival, as well as quality of life. Firstly, the associations between adiposity with inflammation, hepcidin and haemoglobin levels were investigated. Secondly, the effects of hypervolemia on blood pressure and levels of N-terminal fragment of pro-hormone B-type natriuretic peptide (NT-proBNP) were explored. Thirdly, the role of muscle mass and fat mass on all domains of fatigue were studied. Finally, the mechanistic aetiology of physical fatigue was examined by evaluation of muscle mass, muscular and cardiovascular functions, and fatigue perception. This thesis concluded that while adiposity displays significant independent association with inflammation, its role in determining hepcidin and haemoglobin levels remains uncertain. Reduced muscle mass may be correlated with physical fatigue, but independent contribution of fat mass in fatigue remains undefined. Hypervolemia is associated with raised blood pressure and elevated levels of NT-proBNP. The findings from this thesis set the scene for future interventional research and therapeutic strategies.